Data-aided linear fitting blind phase estimation method for coherent optical OFDM system

In this paper, a novel data-aided linear fitting-based (DALF-based) blind phase estimation method for coherent optical orthogonal frequency-division multiplexing (CO-OFDM) is proposed. Similar to our previous work done in the pilot-based blind phase estimation method, the pilot subcarriers are used to transmit unknown amplitude modulation signals in order to improve spectral efficiency. But the so-called pilot subcarriers can be reduced to only two in the DALF-based method, while the conventional pilot-aided-based (PA-based) method requires almost four real pilot subcarriers. A performance comparison of the conventional PA-based and DALF-based phase estimation methods has been demonstrated through a 16-QAM CO-OFDM simulation. The results show that the performance of the proposed DALF-based method is better than the conventional one with higher SE and has the potential in the large capacity CO-OFDM systems.